Corresponding yarn clearers are known from the state of the art and are used for monitoring the yarn produced by the respective spinning means (a rotor with a rotor spinning machine, an air jet spinning nozzle with an air jet spinning machine, etc.) of the spinning station. In addition to short variations in thickness of the yarn, fluctuations in yarn thickness over larger lengths of yarn (several meters), changes in the hairiness of the yarn, or other yarn properties, which could adversely affect the subsequent processing chain of the yarn, such as the enmeshing or interweaving of the same, are typically monitored.
With semi-automatic spinning machines, the detection of yarn defects takes place automatically with the aid of corresponding yarn clearers along with the interruption of yarn production if unacceptable yarn defects are detected. Subsequently, however, the interrupted spinning process must be restarted by initiating a piecing process by an operator. In doing so, it is initially essential that the yarn section having the yarn defect is removed from the remaining yarn.
Since, upon yarn production being stopped, not all of the previously moving components of the spinning station are to be immediately stopped, the yarn defect is usually located on the package after the interruption of yarn production. Thus, a certain length of yarn initially must be drawn out from the package, wherein it must be ensured that the drawn-out yarn also includes the previously detected yarn defect. With short yarn defects, this is still possible with a fair level of reliability, since the operator only has to remove one to two meters of yarn in such a case. For longer yarn defects, with which more than two meters of yarn must be removed, there is a large risk that the yarn section having the yarn defect is not completely removed from the package by the operator. Upon the subsequent piecing process, the yarn section having the yarn defect, or at least a part thereof, is brought into contact with the sliver to be spun, and finally arrives back to the package, without thereby being detected. The task of this invention is to propose an option that takes into account the problem set forth above.